1. Field of the Invention
This invention relates to a piston assembly for an internal combustion engine having a rotatable crankshaft and more particularly to a piston assembly utilizing heat insulated components.
2. Description of the Prior Art
There is currently an industry trend to develop internal combustion engines which can operate at higher combustion temperatures and pressures. One means for obtaining such higher values is to use new heat insulated materials, such as ceramics. Although the ceramic materials exhibit superb heat insulating qualities, they tend to be brittle and stress sensitive and are susceptible to cracking when used in an operating engine. This is especially true when the piston body is primarily constructed from ceramic. Various attempts to use ceramics in pistons have been primarily limited to ceramic inserts and ceramic crowns attached to metallic carriers. Such is taught in U.S. Pat. No. 4,245,611 issued to Mitchell et al in January 1981 and in U.S. Pat. No. 4,114,519 issued to Speaight in September 1978. Even in these designs, there is a likelihood that peak stress loading and unsymmetrical stress patterns will develop across the surface of the piston. Such stress patterns are partially caused by the use of a conventional piston pin.
Now a piston assembly has been invented which will provide a symmetrical stress pattern across the surface of the piston and will permit a greater percentage of the piston to be constructed of a ceramic material.